Novel adsorbent hollow fibres for oxygen concentration

The research examined the development of adsorbent hollow fibres as a low pressure drop structure for the production of oxygen-enriched air. The potential benefits of using a low pressure drop flexible adsorbent structure with molecular sieving properties over a bed packed with pellets include a low attrition resistance which could extend the life of the adsorbent structure. Highly macroporous, highly adsorbent loaded (up to 90 wt%) fibres were produced. By increasing adsorbent density, the separative performance and nitrogen loading were improved. The separative performance of the adsorbent fibre was found to be slightly inferior to that of the bed of smaller 0.4–0.8 mm beads, as the diffusion path length was longer in the fibres and caused increased mass transfer resistances within the macroporous structure. The pressure drop through the fibre was found to be 40 to 70 times lower than that through an equivalent packed bed of 0.4–0.8 mm beads. This experimental feasibility study has demonstrated that the novel zeolite fibre configuration shows good potential for the production of oxygen-enriched air in a low energy, short cycle time, pressure swing process. The challenges of improving the performance of the adsorbent fibres and their operating parameters are described.